Data from the CMR GUIDE trial—shared at ESC Congress 2026 and published concurrently in JAMA—showed that fitting an ICD did not lead to a statistically meaningful drop in sudden cardiac death (SCD) or hemodynamically significant ventricular arrhythmia (HSVA) relative to an implantable loop recorder (ILR) among individuals with myocardial scar and an LVEF ranging from 36% to 50%.
Across 18 medical centers situated in Germany, Australia, and the UK, trial investigators assigned roughly 350 participants randomly to receive either an ILR or a primary prevention ICD. Researchers tracked participants over a median follow-up period of 6.3 years to evaluate hard clinical endpoints in this specific cardiac population.
CMR GUIDE Trial Results and Patient Demographics
Trial records indicate that the median age among participants was 65 years, with females accounting for 18%, an ischemic etiology present in 72%, and an LVEF of 40% or higher noted in 70%.
Overall results showed the primary outcome of SCD or HSVA occurred in 14 patients (7.8%) in the ICD group compared with 16 patients (9.2%) in the ILR group. Broken down by individual components, SCD occurred in 3 patients (1.7%) in the ICD group vs. 10 patients (5.8%) in the ILR group, while HSVA occurred in 12 patients (6.7%) vs. 6 patients (3.5%), respectively.
Did you know? Study authors observed that rates of heart failure–related hospitalization, cardiovascular mortality, and all-cause mortality remained comparable across both study arms.
Age-Specific Outcomes and Expert Perspectives
Furthermore, an evaluation of subgroups that was planned beforehand revealed that the primary endpoint happened less frequently among study participants under 70 years of age given an ICD, whereas no such reduction appeared in those 70 and older.
“Overall, the primary endpoint was neutral,” said Principal Investigator Joseph Selvanayagam, MD, from Flinders University, Flinders Medical Centre in Adelaide, Australia. “However, younger patients appeared to derive clinical benefit from ICDs. We suggest that data from the CMR GUIDE trial are discussed with younger patients in whom ICDs may be an option in a shared decision-making process.”
Accompanying editorial commentary provided additional context regarding the clinical implications of the study. In a related editorial comment, Sana M. Al-Khatib, MD, FACC, highlights that “one of the main benefits of the CMR GUIDE trial is that it highlights the need for more randomized clinical trials of ICDs for primary prevention guided by LGE-CMR in patients with an LVEF greater than 35%,” stressing that “such data are urgently needed.”
Frequently Asked Questions
What was the primary finding of the CMR GUIDE trial?
Findings reported from the CMR GUIDE trial at ESC Congress 2026—and simultaneously published in JAMA—indicated that placing an ICD failed to yield a significant decrease in hemodynamically significant ventricular arrhythmia (HSVA) or sudden cardiac death (SCD) versus an implantable loop recorder (ILR) within a cohort possessing myocardial scar and an LVEF between 36% and 50%.
How many patients participated in the study?
The study involved about 350 subjects split between an ILR and a primary prevention ICD, hailing from 18 distinct centers located in Germany, the UK, and Australia.
Were there any subgroups that benefited from ICDs?
Yes. Moreover, a preplanned subgroup analysis demonstrated that the primary endpoint was observed at a lower rate in individuals under 70 years old who were treated with an ICD, but not in patients aged 70 and older.
What did experts recommend for clinical practice?
“We suggest that data from the CMR GUIDE trial are discussed with younger patients in whom ICDs may be an option in a shared decision-making process.”
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